Squaring a rounded corner

[mrjackson]

Is there a quick tool or technique to turn a rounded corner into a squared corner? A corner with a dynamic corner point can drag it to "close to" a square corner, but not really. 

One of the Astute tools might do it, but I haven't explored it. 

Thanks in advance. MJ

[Kurt Gold]

Yes, there may be some ways.

Can you share a sample Illustrator file with some further instructions?